This paper introduces a desktop biofibers spinning machine to enable the exploration of biobased fibers for sustainable smart textile design. Smart textiles, which integrate electronics with traditional textiles, face significant sustainability challenges due to the combination of textile and electronic waste streams. The proposed machine allows for the production of customizable biofibers from biobased materials, such as gelatin, which are biodegradable, compostable, and recyclable. The machine is modeled after fiber wet spinning, a process commonly used to produce synthetic fibers with customized properties from liquid solutions. However, it has been adapted to work specifically with biobased materials instead of traditional petroleum or synthetic polymer-based solutions. The machine enables the prototyping, production, and customization of biofibers, which can be integrated into smart textile applications. The paper describes the machine's design, a usage walkthrough, considerations for fiber spinning, and an exploration of various formulations to make gelatin biofibers. It also provides several examples of biofibers integrated into smart textile applications and discusses lessons learned from working with biofibers and the unique opportunities our machine brings to the fiber design space in HCI. The paper also explores the sustainability challenges in smart textiles, the challenges in fiber and biofiber production techniques, and the material exploration using the biofibers spinning machine. The paper concludes with example applications of the machine in smart and shape-changing textiles for HCI, demonstrating the incorporation of biofibers into textiles through dissolving for recycling and reharvesting, and dissolving and swelling to trigger interaction.This paper introduces a desktop biofibers spinning machine to enable the exploration of biobased fibers for sustainable smart textile design. Smart textiles, which integrate electronics with traditional textiles, face significant sustainability challenges due to the combination of textile and electronic waste streams. The proposed machine allows for the production of customizable biofibers from biobased materials, such as gelatin, which are biodegradable, compostable, and recyclable. The machine is modeled after fiber wet spinning, a process commonly used to produce synthetic fibers with customized properties from liquid solutions. However, it has been adapted to work specifically with biobased materials instead of traditional petroleum or synthetic polymer-based solutions. The machine enables the prototyping, production, and customization of biofibers, which can be integrated into smart textile applications. The paper describes the machine's design, a usage walkthrough, considerations for fiber spinning, and an exploration of various formulations to make gelatin biofibers. It also provides several examples of biofibers integrated into smart textile applications and discusses lessons learned from working with biofibers and the unique opportunities our machine brings to the fiber design space in HCI. The paper also explores the sustainability challenges in smart textiles, the challenges in fiber and biofiber production techniques, and the material exploration using the biofibers spinning machine. The paper concludes with example applications of the machine in smart and shape-changing textiles for HCI, demonstrating the incorporation of biofibers into textiles through dissolving for recycling and reharvesting, and dissolving and swelling to trigger interaction.